Kinetic Modeling of Heat and Mass Transfer During Deep Fat Frying of Churro

Abstract

The effect of deep fat frying temperatures, ranging from 160 to 190 o C, on frying parameters including the heat transfer coefficient (he), mass transfer coefficient (ke) and effective moisture diffusivity (De) were investigated during deep fat frying of churro that was fried as dough pastry. Therefore experimental studies were conducted for both heat and mass transfer phenomena and mathematical model was developed for simultaneous transfer by using Newman technique for churro actual geometry (3-D cylindrical shape). Fourier's and Fick's laws were applied for the computation of coefficients of heat and mass transfer. The he coefficients were 437.360-93.535 W/m 2 K in the temperatures range of 160 to 190 o C. However, the value of ke and De increased by an increase in oil temperature during frying. The maximum values were determined as 17.36×10 -5 m/s and 2.48×10 -5 m 2 /s at 190 o C for ke and De, respectively. Model and experimental data had good agreement and the transfer coefficients followed the first order kinetic model with high R 2 and low root mean square error (RMSE) values. The Arrhenius equation was applied to describe the relationship between the effective moisture diffusivity and deep fat frying temperature, so the value of activation energy was calculated as 63.546 kj/mol.